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Abstract:

A turbine blade assembly (106) includes a turbine blade (124) and a
moveable surface (126) supported for lateral displacement across the
turbine blade. A wind turbine (100) includes a base structure (102), a
turbine body (104) and a turbine blade assembly (106) operatively
connected to the turbine body. A method (500) of operating a wind turbine
is also included.

Claims:

1-2. (canceled)

3. A wind turbine comprising: a base structure; a turbine body including
first and second body portions, said first body portion supported on said
base structure and including a first axis extending longitudinally along
said first body portion, said second body portion supported on said first
body portion for rotation about said first axis; and, a turbine blade
assembly supported on said second turbine body for rotation therewith
about said first axis, said turbine blade assembly including: a turbine
blade having a longitudinal length, a first longitudinal edge, a second
longitudinal edge spaced laterally from said first longitudinal edge, a
first side extending longitudinally along at least a portion of said
length between said first and second longitudinal edges, and a second
side extending longitudinally along at least a portion of said length
between said first and second longitudinal edges and generally opposite
said first side, said blade including a proximal end operatively
connected to said second turbine body and a distal end spaced
radially-outwardly from said proximal end; a first endless band including
a first outer surface and a first band width, said first endless band
oriented such that said first band width extends longitudinally along
said blade, said first endless band supported on said blade such that
said first outer surface is exposed along at least a portion of at least
one of said first and second sides of said blade and is capable of
lateral movement along said at least one of said first and second sides
such that a relative velocity can be maintained between said first outer
surface and said at least one of said first and second sides of said
blade; and, a second endless band spaced longitudinally along said blade
from said first endless band, said second endless band including a second
outer surface and a second band width, said second endless band oriented
such that said second band width extends longitudinally along said blade,
said second endless band supported on said blade such that said second
outer surface is exposed along at least a portion of at least one of said
first and second sides of said blade and is capable of lateral movement
along said at least one of said first and second sides; said wind turbine
having a theoretical maximum wind speed for operation and during use
under the influence of wind traveling at wind speeds less than or equal
to said theoretical maximum in which said first longitudinal edge acts as
a leading edge of said blade, said second longitudinal edge acts as a
trailing edge of said blade, said first side operates as a pressure side
of said blade and said second side operates as a suction side of said
blade; said first endless band is displaced relative to said blade such
that at least one of: said first outer surface of said first endless band
moves laterally along said first side of said blade in a direction
extending from said trailing edge toward said leading edge; and, said
first outer surface of said first endless band moves laterally along said
second side of said blade in a direction extending from said leading edge
toward said trailing edge; and, said second endless band displaced
relative to said blade such that at least one of: said outer second
surface of said second endless band moves laterally along said first side
of said blade in a direction extending from said trailing edge toward
said leading edge; and, said second outer surface of said second endless
band moves laterally along said second side of said blade in a direction
extending from said leading edge toward said trailing edge.

4. A wind turbine according to claim 3, wherein said first outer surface
of said first endless band moves at a first surface speed and said second
outer surface of said second endless band moves at a second surface speed
that is different from said first surface speed.

5. A wind turbine according to claim 4, wherein said second endless band
is positioned toward said distal end with respect to said first endless
band, and said second surface speed is less than said first surface
speed.

6. (canceled)

7. A wind turbine comprising: a base structure; a turbine body including
first and second body portions, said first body portion supported on said
base structure and including a first axis extending longitudinally along
said first body portion, said second body portion supported on said first
body portion for rotation about said first axis; and, a turbine blade
assembly supported on said second turbine body for rotation therewith
about said first axis, said turbine blade assembly including: a turbine
blade having a longitudinal length, a first longitudinal edge, a second
longitudinal edge spaced laterally from said first longitudinal edge, a
first side extending longitudinally along at least a portion of said
length between said first and second longitudinal edges, and a second
side extending longitudinally along at least a portion of said length
between said first and second longitudinal edges and generally opposite
said first side, said blade including a proximal end operatively
connected to said second turbine body and a distal end spaced
radially-outwardly from said proximal end; a first endless band including
a first outer surface and a first band width, said first endless band
oriented such that said first band width extends longitudinally along
said blade, said first endless band supported on said blade such that
said first outer surface is exposed along at least a portion of at least
one of said first and second sides of said blade and is capable of
lateral movement along said at least one of said first and second sides
such that a relative velocity can be maintained between said first outer
surface and said at least one of said first and second sides of said
blade; and, a second endless band spaced longitudinally along said blade
from said first endless band, said second endless band including a second
outer surface and a second band width, said second endless band oriented
such that said second band width extends longitudinally along said blade,
said second endless band supported on said blade such that said second
outer surface is exposed along at least a portion of at least one of said
first and second sides of said blade and is capable of lateral movement
along said at least one of said first and second sides; said wind turbine
having a theoretical maximum wind speed for operation and during use
under the influence of wind traveling at wind speeds greater than said
theoretical maximum in which said first longitudinal edge acts as a
leading edge of said blade, said second longitudinal edge acts as a
trailing edge of said blade, said first side operates as a pressure side
of said blade and said second side operates as a suction side of said
blade; said first endless band is displaced relative to said blade such
that at least one of: said outer surface of said first endless band
moving laterally along said first side of said blade in a direction
extending from said leading edge toward said trailing edge; and, said
outer surface of said first endless band moving laterally along said
second side of said blade in a direction extending from said trailing
edge toward said leading edge; and, said second endless band displaced
relative to said blade such that at least one of: said outer second
surface of said second endless band moves laterally along said first side
of said blade in a direction extending from said leading edge toward said
trailing edge; and, said second outer surface of said second endless band
moves laterally along said second side of said blade in a direction
extending from said trailing edge toward said leading edge.

8. A wind turbine according to claim 7, wherein said first outer surface
of said first endless band moves at a first surface speed and said second
outer surface of said second endless band moves at a second surface speed
that is different from said first surface speed.

9. A wind turbine according to claim 8, wherein said second endless band
is positioned toward said distal end with respect to said first endless
band, and said second surface speed is greater than said first surface
speed.

10-23. (canceled)

24. A wind turbine blade assembly comprising: a wind turbine blade
including a longitudinal length extending between opposing first and
second ends, a first edge extending longitudinally along said blade, a
second edge extending longitudinally along said blade in laterally spaced
relation to said first edge, a first side extending longitudinally along
said blade and laterally between said first and second edges, and a
second side extending longitudinally along said blade and laterally
between said first and second edges generally opposite said first side;
and, a first endless band including a first outer surface and a first
band width, said first endless band oriented such that said first band
width extends longitudinally along said blade, said first endless band
supported on said blade such that said first outer surface is exposed
along at least a portion of at least one of said first and second sides
of said blade and is capable of lateral movement along said at least one
of said first and second sides such that a first relative velocity can be
maintained between said first outer surface and said at least one of said
first and second sides of said blade; and, a second endless band that
includes a second outer surface and a second band width, said second
endless band disposed in longitudinally-spaced relation to said first
endless band and oriented such that said second band width extends
longitudinally along said blade, said second endless band supported on
said blade such that said second outer surface is exposed along at least
a portion of at least one of said first and second sides of said blade
and is capable of lateral movement along said at least one of said first
and second sides such that a second relative velocity can be maintained
between said second outer surface and said at least one of said first and
second sides of said blade.

25. A wind turbine blade assembly according to claim 24, wherein said
first band has a first length and said second band has a second length
that is different from said first length.

26. A wind turbine blade assembly according to claim 24, wherein said
first endless band includes a first inner surface and is supported on
said blade between first and second support elements, said first support
element drivably engaging said first inner surface of said first endless
band, and second support element spaced laterally from said first support
element.

27. A wind turbine blade assembly according to claim 26, wherein said
second endless band includes a second inner surface and is supported on
said blade between third and fourth support elements, said third support
element drivably engaging said second inner surface of said second
endless band, and said fourth support element spaced laterally from said
third support element.

28. A wind turbine blade assembly according to claim 24 further
comprising a rotational motion source operatively connected to at least
one of said first and second endless bands for imparting lateral movement
thereto.

29. A wind turbine blade assembly according to 28, wherein said
rotational motion source is operatively connected to each of said first
and second endless bands such that said first and second endless bands
can be moved synchronously relative to one another.

30. A wind turbine blade assembly according to claim 28, wherein said
rotational motion source is a first rotational motion source operatively
connected to said first endless band, and said wind turbine blade
assembly further comprises a second rotational motion source operatively
connected to said second endless band such that said first and second
endless bands can be moved independently relative to one another.

31. A wind turbine blade assembly comprising: a wind turbine blade
including a longitudinal length extending between opposing first and
second ends, a first edge extending longitudinally along said blade, a
second edge extending longitudinally along said blade in laterally spaced
relation to said first edge, a first side extending longitudinally along
said blade and laterally between said first and second edges, and a
second side extending longitudinally along said blade and laterally
between said first and second edges generally opposite said first side; a
first endless band including a first outer surface and a first band
width, said first endless band oriented such that said first band width
extends longitudinally along said blade, said first endless band
supported on said blade such that said first outer surface is exposed
along at least a portion of at least one of said first and second sides
of said blade and is capable of lateral movement along said at least one
of said first and second sides such that a first relative velocity can be
maintained between said first outer surface and said at least one of said
first and second sides of said blade; and, a second endless band that
includes a second outer surface and a second band width; said first
endless band supported on said blade such that said first outer surface
is exposed along at least a portion of said first side of said blade and
is capable of lateral displacement therealong; and, said second endless
band oriented such that said second band width extends longitudinally
along said blade, and said second endless band supported on said blade
such that said second outer surface is exposed along at least a portion
of said second side of said blade and is capable of lateral displacement
therealong and such that a second relative velocity can be maintained
between said second outer surface and said second side of said blade.

32. A wind turbine blade assembly according to claim 31 further
comprising a rotational motion source operatively connected to at least
one of said first and second endless bands for imparting lateral movement
thereto.

33. A wind turbine blade assembly according to 32, wherein said
rotational motion source is operatively connected to each of said first
and second endless bands such that said first and second endless bands
can be moved synchronously relative to one another.

34. A wind turbine blade assembly according to claim 32, wherein said
rotational motion source is a first rotational motion source operatively
connected to said first endless band, and said wind turbine blade
assembly further comprises a second rotational motion source operatively
connected to said second endless band such that said first and second
endless bands can be moved independently relative to one another.

35. A wind turbine blade assembly according to claim 34 further comprises
a control system for selectively operating said first and second
rotational motion sources.

36-39. (canceled)

40. A wind turbine blade assembly according to claim 31, wherein said
first side of said blade is aerodynamically distinct from said second
side of said blade such that an airfoil-shaped cross-section is formed
along at least a portion of said longitudinal length of said blade.

41. A wind turbine blade assembly according to claim 31, wherein said
first and second endless band is one bands are two of a plurality of
endless bands supported along said longitudinal length of said blade,
said plurality of endless bands including from two (2) to fifty (50)
endless bands.

42-51. (canceled)

Description:

INCORPORATION BY REFERENCE

[0001] U.S. Pat. Nos. 6,322,024 and 6,824,109, both to the inventor of the
present application, disclose the use of moving bands in connection with
fixed wing aircraft. The entire disclosure of each of these documents is
hereby incorporated herein by reference.

BACKGROUND

[0002] The subject matter of the present disclosure broadly relates to the
art of energy conversion systems and, more particularly, to a wind
turbine capable of converting wind energy into rotational mechanical
energy, such as may be used to operate a generator to produce electrical
energy, for example, as well as a method of operating a wind turbine.

[0003] The subject matter of the present disclosure finds particular
application and use in connection with wind turbine, and is shown and
described herein with preference thereto. It will be appreciated,
however, that the subject matter of the present disclosure is amenable to
use in a variety of other applications and/or environments, such as air
moving devices (e.g., fans) and other power generation systems (e.g.,
turbines), for example. As such, it is to be understood that the specific
reference herein to use on and/or in association with wind turbines is
merely one example of such use not intended to be limiting.

[0004] Wind turbines are well known and commonly used to convert wind
energy into rotational mechanical output that can be used for any
suitable purpose, such as to operate a generating system or device for
the production of electrical power, for example. Current wind turbine
designs typically include a base structure that supports a turbine
housing at a level that is elevated with respect to the surrounding
geography (i.e., land surface or water level). In many constructions, two
or more turbine blades are supported on a hub of the turbine housing. The
hub is capable of rotating in response to air currents (i.e., wind) that
are acting on the blades. In this manner, wind energy can be converted to
rotational mechanical energy for electrical power generation and/or other
purposes.

[0005] Notwithstanding the overall success of modern wind turbine designs,
one or more characteristics have been observed that may operate to limit
the application and/or use of wind turbines. These characteristics may
also reduce the overall cost effectiveness of wind turbines under certain
conditions. As such, these issues may lead to a reduction in the
installation and use of wind turbines, where increased installation and
usage might be preferred.

[0006] One such characteristic involves the conditions of operation of
wind turbines. That is, there are known to be minimum and maximum wind
speed thresholds outside of which operation of a wind turbine is
generally avoided. Of course, these minimum and maximum wind speed
thresholds will vary from wind turbine to wind turbine and from situation
to situation.

[0007] At one extreme, it is generally acknowledges that there is a
minimum wind speed at which a wind turbine can effectively operate. In
many cases, the minimum wind speed is within a range of from about 5 MPH
to about 8 MPH. As such, wind turbines often remain idle in light wind
conditions.

[0008] At the opposite extreme, it is generally recognized that there is a
maximum wind speed at which a wind turbine may be operated. Often, the
maximum wind speed is greater than 50 MPH. As expected, the maximum wind
speed threshold will relate to the design and construction of the wind
turbine as well as the operational limitations of the electrical
components driven by the turbine. Nonetheless, wind turbines are commonly
stopped during high wind conditions.

[0009] It is believed desirable to develop a wind turbine and method of
operation that overcomes these and/or other disadvantageous
characteristics of known wind turbines and that can operate under a
greater range of wind speeds and/or conditions.

BRIEF DESCRIPTION

[0010] One example of a wind turbine in accordance with the subject matter
of the present disclosure can include a base structure and a turbine body
that includes first and second body portions. The first body portion is
supported on the base structure and includes a first axis extending
longitudinally along the first body portion. The second body portion is
supported on the first body portion for rotation about the first axis. A
turbine blade assembly is supported on the second turbine body for
rotation therewith about the first axis. The turbine blade assembly
includes a turbine blade that has a longitudinal length, a first
longitudinal edge, a second longitudinal edge spaced laterally from the
first longitudinal edge, a first side extending longitudinally along at
least a portion of the length between the first and second longitudinal
edges, and a second side extending longitudinally along at least a
portion of the length between the first and second longitudinal edges and
generally opposite the first side. The turbine blade includes a proximal
end operatively connected to the second turbine body and a distal end
spaced radially-outwardly from the proximal end. A first endless band
includes a first outer surface and a first band width. The first endless
band is oriented such that the first band width extends longitudinally
along the turbine blade. The first endless band is supported on the
turbine blade such that the first outer surface is exposed along at least
a portion of at least one of the first and second sides of the turbine
blade and is capable of lateral movement along the at least one of the
first and second sides. In this manner, a relative velocity can be
maintained between the first outer surface and the at least one of the
first and second sides of the turbine blade.

[0011] One example of a wind turbine blade assembly in accordance with the
subject matter of the present disclosure can include a wind turbine blade
and an endless band. The wind turbine blade includes a longitudinal
length extending between opposing first and second ends, a first edge
extending longitudinally along the blade, a second edge extending
longitudinally along the blade in laterally spaced relation to the first
edge, a first side extending longitudinally along the blade and laterally
between the first and second edges, and a second side extending
longitudinally along the blade and laterally between the first and second
edges generally opposite the first side. The first endless band includes
a first outer surface and a first band width. The first endless band
being oriented such that the first band width extends longitudinally
along the blade. The first endless band being supported on the blade such
that the first outer surface is exposed along at least a portion of at
least one of the first and second sides of the blade and is capable of
lateral movement along the at least one of the first and second sides
such that a first relative velocity can be maintained between the first
outer surface and the at least one of the first and second sides of the
blade.

[0012] One example of a method of operating a wind turbine in accordance
with the subject matter of the present disclosure can include providing a
wind turbine and providing an endless band. The wind turbine can include
a base structure, a turbine body supported on the base structure and at
least one turbine blade. The turbine body can have a
longitudinal-extending turbine body axis, and the at least one turbine
blade can be supported on the turbine body for rotation about the turbine
body axis. The at least one turbine blade includes a longitudinal length
extending between opposing first and second ends, a first edge extending
longitudinally along the blade, a second edge extending longitudinally
along the blade in laterally spaced relation to the first edge, a first
side extending longitudinally along the blade and laterally between the
first and second edges, and a second side extending longitudinally along
the blade and laterally between the first and second edges generally
opposite the first side. The endless band includes a first outer surface
and a first band width. The method also includes orienting the endless
band such that the first band width extends longitudinally along the
blade and supporting the endless band on the blade such that the first
outer surface is exposed along at least a portion of at least one of the
first and second sides of the blade. The method further includes driving
the at least one endless band such that the outer surface moves laterally
along at least one of the first and second sides of the blade between the
first and second edges thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a front elevation view of one example of a wind turbine
in accordance with the subject matter of the present disclosure.

[0014]FIG. 2 is a side elevation view of the wind turbine in FIG. 1 shown
in partial cross-section.

[0015]FIG. 3 is a side view of one example of a turbine blade assembly in
accordance with the subject matter of the present disclosure, such as may
be included on the wind turbine in FIGS. 1 and 2.

[0016]FIG. 4 is an enlarged detail view of the portion of the turbine
blade assembly shown in Detail 4 of FIG. 3.

[0017]FIG. 5 is a cross-sectional view of the turbine blade assembly in
FIGS. 3 and 4 taken from along line 5-5 in FIG. 4.

[0018]FIG. 6 is a side view of another example of a turbine blade
assembly in accordance with the subject matter of the present disclosure,
such as may be included on the wind turbine in FIGS. 1 and 2.

[0019]FIG. 7 is an enlarged detail view of the portion of the turbine
blade assembly shown in Detail 7 of FIG. 6.

[0020]FIG. 8 is a cross-sectional view of the turbine blade assembly in
FIGS. 6 and 7 taken from along line 8-8 in FIG. 7.

[0021]FIG. 9 is a cross-sectional schematic representation of a further
example of a turbine blade assembly in accordance with the subject matter
of the present disclosure that includes a separate movable surface on
each side of a turbine blade.

[0022]FIG. 10 is a graphical representation of one example of a method of
operating a wind turbine in accordance with the subject matter of the
present disclosure.

DETAILED DESCRIPTION

[0023] Referring now in greater detail to the drawings, it is to be
understood that the illustrations reference herein are for the purposes
of demonstrating examples of embodiments of the subject matter of the
present disclosure and that these illustrations and examples are not
intended to be in any way limiting. Additionally, it should be recognized
and appreciated that the drawings are not to scale and that the
proportion of certain features and/or elements may be exaggerated for
purposes of clarity and ease of understanding.

[0024] FIGS. 1 and 2 illustrate a wind turbine 100 that includes a support
or base structure 102, a turbine body 104 that is supported on the base
structure, and at least one turbine blade assembly that is operatively
connected to the turbine body. In the exemplary embodiment shown in FIGS.
1 and 2, a plurality of turbine blade assemblies 106 is shown as being
operatively connected to turbine body 104. It will be appreciated,
however, that any suitable number of turbine blade assemblies can
supported on the turbine body, such as from one (1) to nine (9) turbine
blade assemblies, for example.

[0025] Support or base structure 102 is shown in FIGS. 1 and 2 as having
an approximately-straight configuration extending longitudinally between
a first or lower end 108 and a second or upper end 110. It will be
appreciated that the base structure can be of any type, kind,
configuration and/or construction suitable for supporting turbine body
104 and the one or more turbine blade assemblies at a suitable elevation
above a supporting foundation (not shown), and that base structure 102 is
merely one example of a base structure that could be used. Additionally,
it will be appreciated that a wind turbine in accordance with the subject
disclosure can be installed at any suitable geographic location. As such,
the supporting foundation could, without limitation, be a solid
foundation supported by the ground, a floating structure on a body of
water or even a rooftop (or other elevated portion) of a building or
other structure.

[0026] Base structure 102 is shown in FIG. 2 as including a
longitudinally-extending axis AX1 extending between the first and second
ends thereof. Turbine body 104 is shown as being supported on second end
110 and, in a preferred arrangement, is operatively connected to base
structure 102 such that the turbine body can be rotated about axis AX1.
In this manner, the turbine body and the one or more turbine blade
assemblies supported thereon can be favorably oriented with respect to
the direction of the wind. It will be recognized that the favorable
orientation of a turbine body and one or more turbine blade assemblies of
a wind turbine is generally well understood in the art and that any
suitable arrangement and/or system can be used to control the orientation
of the turbine body and one or more turbine blade assemblies about axis
AX1.

[0027] Turbine body 104 includes a first or front end 112, a second or
tail end 114 and a longitudinal axis AX2 that extends generally between
front and tail ends 112 and 114. As shown in FIG. 2, turbine body 104 can
be oriented in a lengthwise-direction with respect to the wind direction,
as indicated by arrows WND, such that front end 112 and turbine blade
assemblies 106 are facing in an upstream direction and tail end 114 is
disposed in a downstream direction. It will be appreciated, however, that
other configurations and/or constructions of wind turbines may operate in
a different manner.

[0028] Turbine body 104 also includes a first body portion 116 that is
supported on the base structure for rotation about axis AX1, as described
above, and a second body portion 118 that is supported on the first body
portion for rotation about axis AX2. It will be appreciated that second
body portion 118 can be supported on first body portion 116 in any
suitable manner, such as may be known by those of skill in the art.

[0029] With further reference to FIGS. 1 and 2, a plurality of turbine
blade assemblies 106 are operatively connected to second body portion 118
of turbine body 104 for rotation therewith about axis AX2. As will be
described in detail hereinafter, kinetic energy from air currents (i.e.,
wind) acting on turbine blade assemblies 106 cause the turbine blade
assemblies to impart rotational motion to second body portion 118 of the
turbine body. As such, the turbine blade assemblies together with the
second body portion of the turbine body rotate about axis AX2, as
indicated by arrows RT1 and RT2 in FIG. 1.

[0030] Turbine blade assemblies 106 extend radially-outwardly from second
body portion 116 between a first or proximal end 120 and a second or
distal end 122. A longitudinal axis AX3 extends generally between the
proximal and distal ends. In one preferred embodiment, the turbine blade
assemblies are supported on second body portion 116 for rotation about
axis AX3 respectively of each turbine blade assembly, as is generally
indicated by arrows RT3 in FIG. 1. Rotation of the turbine blade
assemblies about axes AX3 permits favorable orientation of the turbine
blade assemblies with respect to the direction of the wind, as is well
understood by those of skill in the art. Additionally, it will be
appreciated that any suitable arrangement and/or control system can be
used to selectively adjust the orientation of the turbine blade
assemblies about axes AX3.

[0031] It will be recognized that turbine blades of a wide variety of
different sizes, shapes, configurations and constructions have been
developed, and that all such variations could not be shown and/or
described in the subject disclosure. For example, turbine blades have
been developed that include straight edges, tapered edges, curved edges,
approximately planar sides, curved sides, symmetrically-shaped sides and
asymmetrically-shaped sides. Additionally, many blades are twisted along
the longitudinal length thereof such that the wind contacts the turbine
blade at different angles at different points along the longitudinal
extent of the turbine blade. Notwithstanding all of the many variations
of turbine blades, it is to be understood that the subject matter of the
present disclosure is broadly capable of use on or otherwise in
association with turbine blades of any suitable type, kind, configuration
and/or construction. As such, it is to be understood that the type, kind,
size, shape, construction, configuration and/or arrangement of turbine
blades shown and described herein are merely exemplary and not intended
to be limiting.

[0032] A turbine blade assembly in accordance with the subject matter of
the present disclosure, such as one of turbine blade assemblies 106, for
example, includes a turbine blade and at least one surface that is
disposed along at least one side of the turbine blade and is moveable
relative to the side of the blade such that the relative speed of the
moveable surface with respect to the wind is different than the relative
speed of the side of the turbine blade would be at that same longitudinal
location. In FIGS. 1 and 2, turbine blade assemblies 106 include a
turbine blade 124 and a surface (schematically represented by shaded area
126) that extends along at least one side of turbine blade 124 and is
moveable in a direction along the at least one side that is approximately
transverse (e.g., perpendicular) to longitudinal axis AX3, as is
represented by arrows AR1. For purposes of clarity and ease of
understanding, a direction approximately transverse (e.g., perpendicular)
to longitudinal axis AX3 may also be referred to herein as a lateral
direction.

[0033] Turning, now, to FIGS. 3-5, one example of a turbine blade assembly
200 that is suitable for use as a turbine blade assembly in accordance
with the subject matter of the present disclosure, such as turbine blade
assemblies 106 in FIGS. 1 and 2, for example, is shown as including a
turbine blade 202 that extends longitudinally between a first or proximal
end 204 and a second or distal end 206 such that longitudinal axis AX3
extends generally therebetween. Turbine blade 202 also includes a first
or leading edge 208 that extends longitudinally along the turbine blade
and a second or trailing edge 210 that extends longitudinally along the
turbine blade in laterally-spaced relation to the leading edge. As can be
observed from FIGS. 3-5, trailing edge 210 is shown as being disposed at
an angle relative to leading edge 208, such a portion of the turbine
blade nearer to distal end 206 will have a lesser lateral dimension than
a portion of the turbine blade nearer to proximal end 204. As one
example, such an arrangement could be due to the turbine blade being
tapered in the lateral direction or, as another example, due to the
turbine blade being twisted along the longitudinal length thereof.

[0034] Turbine blade 202 further includes opposing first and second sides
212 and 214 (FIG. 5) that extend laterally between the leading and
trailing edges of the turbine blade. Depending upon factors such as the
shape of the turbine blade, the direction of rotation of the turbine
blade about axis AX2 and the angle at which the turbine blade is disposed
about axis AX3, one of the first and second sides of the turbine blade
may be referred to as a pressure side with the other of the first and
second sides being referred to as the suction side of the turbine blade.
As will be discussed in greater detail hereinafter, first side 212 could
operate as the pressure side of turbine blade 202 and second side 214
would operate as the suction side of the turbine blade.

[0035] As mentioned above, a turbine blade assembly in accordance with the
subject matter of the present disclosure includes at least one surface
that is moveable in an approximately lateral direction along a side of
the turbine blade. It will be appreciated that any suitable number of one
or more moveable surfaces can be used, such as from one (1) to fifty (50)
different surfaces, for example. Additionally, it will be appreciated
that the at least one moveable surface can take any suitable form,
configuration and/or construction and can be of any suitable size and/or
shape that may be cooperative with the turbine blade on which the at
least one moveable surface is operatively supported. As one example, the
at least one moveable surface can take the form of at least one endless
band that is operatively supported on the turbine blade for movement in
an approximately lateral direction along at least one side of the turbine
blade.

[0036] In the exemplary embodiment shown in FIGS. 3-5, turbine blade
assembly 200 includes a plurality of endless bands 216A-F that are
supported on turbine blade 202 in longitudinally-spaced relation to one
another. It will be appreciated that each of the plurality of bands can
have one of two or more different widths, lengths and/or shapes. Due at
least in part to the shape and/or configuration of turbine blade 202, the
plurality of bands are shown in FIG. 3 as including a plurality of
different widths and lengths. For example, band 216A has a nominal width
W1 and an average length L1, and band 216B has a nominal width W2 that is
less than width W1 and an average length L2 that is less than length L1.
For purposes of clarity of illustration and ease of reading, the length
and width dimensions are not shown for bands 216C-F. However, it will be
appreciated that two or more of the plurality of bands can, optionally,
have the same length and/or width dimensions. For example, bands 216C and
216D are shown as having approximately the same width as one another and
bands 216E and 216F are also shown as having approximately the same width
as one another.

[0037] It will be appreciated that the influence a given moving surface
may have on a turbine blade will vary depending upon the position of the
moving surface along the longitudinal length of the turbine blade. This
is due, at least in part, to the increased distance from axis AX2 at
which force variations attributable to the moving surface will act on the
turbine blade. In one exemplary embodiment of a turbine blade assembly,
the one or more moving surfaces could be provided along only a portion of
the longitudinal length of the turbine blade, such as along the outermost
one-third of the blade, for example. As another exemplary embodiment of a
turbine blade assembly, a plurality of moving surfaces could be spaced
longitudinally along the turbine blade with one or more dimensions (e.g.,
length and/or width) of the moving surfaces decreasing in the direction
of the distal end of the turbine blade.

[0038] If one or more endless bands are used to form the at least one
moving surface on the turbine blade, as illustrated in FIGS. 3-5, for
example, it will be appreciated that the one or more endless bands can be
supported on the turbine blade in any suitable manner and can include any
suitable components and/or devices for permitting the one or more endless
bands to be conveyed along at least one side of the turbine blade. For
example, one arrangement could utilize a first support element disposed
toward the leading edge of the turbine blade and a second support element
disposed in laterally-spaced relation to the first support element toward
the trailing edge of the turbine blade. The one or more endless bands can
then be supported between these laterally-spaced support elements.

[0039] One exemplary arrangement is shown in greater detail in FIGS. 4 and
5 in which the first support element includes a roller 218 supported on
turbine blade 202 for rotation about a longitudinally-extending axis AX4
(FIG. 5). Roller 218 can be supported on the turbine blade in any
suitable manner, such as by using a pair of spaced-apart bearing elements
(not shown), for example. Additionally, roller 218 can be supported in
any suitable lateral position along turbine blade 202 toward the leading
edge thereof. In the exemplary embodiment shown, roller 218 is supported
in approximate alignment with fixed portions 220 of the turbine blade,
which fixed portions at least partially form leading edge 208 together
with rollers 218. For purposes of clarity of illustration and ease of
understanding, rollers 218 are shown as being approximately cylindrical.
However, it will be appreciated that any other configuration and/or
arrangement could alternately be used, such as crowned rollers or tapered
rollers, for example.

[0040] Another example of a support element that may be suitable for use
in supporting an endless belt includes a plurality of bearing elements
222 spaced longitudinally along an edge of the turbine blade, such as
along trailing edge 210, for example. In one exemplary arrangement, the
plurality of bearing elements can be approximately aligned with fixed
portions 224 of the turbine blade so that the plurality of bearing
element together with the fixed portions at least partially form trailing
edge 210. As one example, a plurality of wheels or roller elements could
be longitudinally spaced along the leading or trailing edge of the
turbine blade. Such a plurality of wheels or roller elements could rotate
independently of one another to permit endless belts of a non-uniform
length to be laterally conveyed about the turbine blade. As another
example, plurality of bearing elements 222 can include one or more
longitudinally-extending rows of spherical bearings 226 (i.e. ball
bearings) that are suitably retained on the turbine blade, such as by
using a ball bearing cage or other structure (not shown), for example.

[0041] The one or more endless bands (e.g., endless bands 216A-F) can be
moved or otherwise conveyed along the one or more sides of the turbine
blade in any suitable manner, such as by using one or more rotational
motions sources operatively connected to the endless bands. As one
example, a single drive shaft could extend longitudinally outwardly along
the length of the turbine blade. The single drive shaft could be
operatively connected to a drive element suitable for conveying the
endless bands in a substantially synchronous manner. As another example,
a plurality of motors or other rotational motion sources could be
supported in longitudinally-spaced relation along the length of the
turbine blade. Each of the plurality of motors could be operatively
connected to a drive element suitable for conveying one or more of the
endless bands. In such an arrangement, one or more of the endless bands
could be independently controlled from the remaining one or more endless
bands. As shown in FIGS. 4 and 5, an electric motor 228 can be
operatively connected to each of rollers 218 for driving the same.
Rollers 218 can be adapted to drivably engage one or more endless bands
and convey or otherwise laterally move the one or more endless bands
along at least one side of the turbine blade.

[0042] In the exemplary arrangement shown in FIGS. 4 and 5, endless band
216F drivably engaged by outer surface 230 of roller 218. Electric motor
228 is operatively connected to roller 218, such as by way of a suitable
transmission element 232 (e.g., a transmission belt or gear set). By
selectively operating electric motor 228, endless band 216F can be
selectively moved with respect to first and second sides 212 and 214 of
turbine blade 202, as indicated by arrows AR2. It will be appreciated
that each of the one or more electric motors or other rotational motion
sources can be controlled in any suitable manner. For example, electric
motors 228 in FIG. 4 are shown as being in communication with a suitable
control system 234, such as by way of communication lines 236, for
example, that is adapted to selectively control the speed and direction
of rotation of electric motors 228 to achieve a desired performance
characteristic of the one or more surfaces (e.g., endless bands) driven
thereby.

[0043] As indicated in FIG. 5, a turbine blade, such as turbine blade
assembly 200, for example, is typically disposed at an angle with respect
to the wind direction, as is indicated by angular reference dimension AOA
relative to arrow WND. As discussed above, the angle of attack may vary
along the longitudinal length of the turbine blade, such as where the
turbine blade is of a twisted configuration. In such case, an adjacent
endless band 216E may be disposed at an angle with respect to endless
band 216F, as is indicated by angular reference dimension AG1. Though the
angle of attack may vary due to the configuration of the turbine blade,
the direction of rotation about axis AX2 (FIG. 2), which is represented
in FIG. 5 by arrow RT1, is generally transverse (e.g., perpendicular) to
the wind direction.

[0044] In the exemplary arrangement shown in FIGS. 3-5, endless bands
216A-F extend peripherally about the full exterior of discrete
longitudinal portions of the turbine blade. That is, endless bands are
conveyed along first side 212, around one of leading edge 208 or trailing
edge 210, along second side 214 and around the other of the leading or
trailing edges and back to the first side in a substantially continuous
manner.

[0045] Another example of a turbine blade assembly 300 is shown in FIGS.
6-8 in which the moving surfaces only extend along the first and/or
second sides of the turbine blade without extending about the leading
and/or trailing edges thereof. Turbine blade assembly 300 includes a
turbine blade 302 that extends longitudinally between a first or proximal
end 304 and a second or distal end 306. Turbine blade 302 includes a
leading edge 308 that extend longitudinally along the turbine blade and a
trailing edge 310 that extends longitudinally along the turbine blade in
laterally spaced relation to leading edge 308. Optionally, the turbine
blade could include removable trailing edge sections 310A-F (FIG. 6) that
could be removably secured on or along the turbine blade to provide
access to the interior of the turbine blade, such as may be useful for
maintenance and repair, for example. Turbine blade 302 also includes
opposing first and second sides 312 and 314 (FIG. 8) that extend
laterally between the leading and trailing edges.

[0046] Turbine blade assembly 300 also includes at least one surface that
is moveable in an approximately lateral direction along a side of the
turbine blade. As shown in the exemplary arrangement in FIGS. 6-8,
turbine blade assembly includes a plurality of endless bands 316A-F
disposed in longitudinally-spaced relation with respect to one another
along the length of turbine blade 302. As discussed above with regard to
endless bands 216A-F, endless bands 316A-F are shown as having one of two
or more widths and lengths. Endless bands 316A-F differ from those shown
in FIGS. 3-5 in that endless bands 316A-F are of an approximately uniform
shape.

[0047] Endless bands 316A-F are shown extending between laterally
spaced-apart support elements that permit the endless bands to be
conveyed or otherwise moved with respect to one or more of the first and
second sides of the turbine blade. As one example, the endless bands
could be supported between rollers 318 and 320. Roller 318 drivably
engaging the endless bands toward the leading edge of the turbine blade
assembly and roller 320 being freely rotating to permit displacement of
the endless band thereabout. It will be appreciated that cylindrical
rollers, which are shown in FIGS. 6-8, may be used in conjunction with
endless bands 316A-F, which are approximately uniformly-shaped. However,
support elements of any other suitable shape and/or configuration could
alternately be used in connection with other constructions and/or shapes
of endless bands, such as crowned or tapered rollers, for example.

[0048] Rollers 318 or other support elements that may be suitable for
drivably engaging one or more of endless bands 316A-F can be operatively
connected to a rotational motion source in any suitable manner. As one
example, one or more electric motors could be longitudinally spaced along
the length of the turbine blade and operatively connected to one or more
of the drive elements. As another example, a drive shaft 322 or other
rotational motion source could extend longitudinally outwardly along the
length of the turbine blade and be operatively connected to one or more
of the drive elements (e.g., roller 318), such as by way of a suitable
transmission element 324 (e.g., a transmission belt or gear set).

[0049] First side 312 of turbine blade 302 also includes first and second
laterally-spaced openings 326 and 328. Similarly, second side 314 of the
turbine blade includes first and second laterally-spaced openings 330 and
332. During operation, endless band 316F is conveyed around drive roller
318 and the first opening in one of the first and second sides, depending
upon the direction in which the endless band is being displaced. The
endless band is further displaced along the corresponding side of the
turbine body and returns toward support roller 320 through the second
opening in that first or second side. The endless band would continue to
be displaced around support roller 320 and exit from the second opening
in the opposing one of the first and second sides. The endless band is
then further displaced along that opposing side toward the first opening
therein through which the endless band returns to be drivably engaged by
drive roller 318. It will be recognized that similar openings are
provided along both sides of the longitudinal length of the turbine blade
such that the one or more other endless bands can be similarly convey
along at least a portion of the sides of the turbine blade.

[0050] Additionally, or in the alternative, a turbine blade assembly, such
as turbine blade assembly 106, 200 and/or 300, for example, can
optionally include a first endless band operatively disposed along a
first side of the turbine blade and a second endless belt that is
operatively disposed along a second side of the turbine blade. FIG. 9
schematically represents a turbine blade assembly 400, such as has been
described above, that includes a turbine blade 402 that has a first or
leading edge 404 and a second or trailing edge 406 that is disposed in
laterally spaced relation to the leading edge, such as has been
previously described. Turbine blade 402 also includes a first side 408
that extends laterally between the leading and trailing edges, and a
second side 410 that extends laterally between the leading and trailing
edges generally opposite first side 410.

[0051] Turbine blade assembly 400 also includes a first endless band 412
operatively disposed for movement along first side 408. It will be
appreciated that first endless band 412 can be supported between
laterally-spaced support elements, such as rollers 414 and 416.
Additionally, roller 414 can be operatively connected to a suitable
rotational motion source 418 (e.g., an electric motor or drive shaft),
such as by way of a suitable transmission element 420 (e.g., a
transmission belt or gear set). First side 408 can be adapted to permit
egress and return of endless band 412, such as has been discussed above
with regard to first side 312, for example.

[0052] Turbine blade assembly 400 further includes a second endless band
422 that is operatively disposed for movement along second side 410 of
turbine blade 402. Second endless band 422 can be similarly supported for
movement between laterally-spaced support elements, such as rollers 424
and 426, for example. Roller 424 can be operatively connected to a
suitable rotational motion source, such as rotational motion source 418
by way of a separate transmission element, for example. Alternately,
roller 424 could be operatively connected to a separate rotational motion
source 428 (e.g., an electric motor or drive shaft), such as by way of a
suitable transmission element 430 (e.g., a transmission belt or gear
set). Second side 410 can also be adapted to permit egress and return of
endless belt 422, such as has been discussed above with regard to second
side 314, for example.

[0053] Though not shown in the drawings, it will be appreciated that any
suitable number of endless bands, such as from one (1) to fifty (50), for
example, could be longitudinally-spaced along the first and/or second
sides of a turbine blade. Additionally, it will be appreciated that any
combination of quantity, width, length and/or configuration of endless
bands could be used.

[0054] The at least one moveable surface operatively disposed on or along
a turbine blade, such as one of endless bands 126, 216A-F, 316A-F, 412
and/or 422, for example, can be formed from any suitable material or
combination of materials, such as metal, plastic and/or fabric, for
example. Metal material could include stainless steel sheet, for example.
Plastic material could include any suitable polymeric film, such as
polyester film, for example. Fabric material could include any suitable
elastomeric or non-elastomeric, woven or non-woven material having one or
more plies formed of filaments of one or more types and/or kinds of
material.

[0055] Reference is now made to the general operation and use of a turbine
blade assembly in accordance with the subject matter of the present
disclosure that includes a turbine blade and at least one moveable
surface supported on or along at least one side of the turbine blade. As
mentioned above, turbine blades are typically disposed at an angle
relative to the wind direction. This angle is often referred to in the
art as the angle of attack and is represented in FIG. 5 by angular
reference dimension AOA, as has been previously discuss. As the air
currents (i.e., wind) flow past the turbine blade, a force is generated
on the turbine blade due to the pressure of the air current acting on the
exposed side of the turbine blade. This force can be separated into a
first directional component that acts in the direction of the wind and a
second directional component that acts approximately transverse (e.g.,
perpendicular) to the first directional component. This second
directional component can act to displace the turbine blade about the
axis of rotation.

[0056] It will be appreciated, however, that in current turbine blade
designs, forces attributable to or otherwise associated with the angle of
attack represent only a portion of the overall forces acting on a turbine
blade. Another portion of the overall forces acting on a turbine blade
are attributable to the use of turbine blades having an airfoil design or
cross-section. As is well understood in the art, air currents flowing
past a turbine blade having an airfoil design will generate a first air
pressure acting on one side and a second, different air pressure acting
on the opposing side of the turbine blade. The generation of these two
different air pressures is generally believed to be due to air flowing
across the two different sides of the turbine blade at two different
speeds, as is well understood in the art. Accordingly, the air flowing at
a first speed (e.g., a higher speed) across one side of the turbine blade
would be expected to generate a different pressure (e.g., a lower
pressure) on the surface than the air flowing at a second speed (e.g., a
lower speed) across the opposing side of the turbine blade (e.g., a
higher pressure side). As a result, one side of the turbine blade is
often referred to as the pressure side of the turbine blade with the
opposing side being referred to as the suction side.

[0057] Forces due to differential air pressures acting on a turbine blade
(i.e., aerodynamic forces other than those associated with the angle of
attack) can also be resolved into a first directional component that acts
in the direction of the wind and a second directional component that acts
approximately transverse (e.g., perpendicular) to the first directional
component. It is generally desirable to orient a turbine blade such that
the portion of the force attributable to the angle of attack (i.e., the
second directional component thereof) and the portion of the force
attributable to differential air pressures (i.e., the second directional
component thereof) are acting in the same direction to cause displacement
of the turbine blade about the axis of rotation.

[0058] Generally, it will be appreciated that the at least one moveable
surface supported on a turbine blade is capable of displacement in either
of two lateral directions with respect to the side of the turbine blade.
One such lateral direction will be approximately the same as the
direction in which the air current (i.e., the wind) is flowing. The
second lateral direction will be generally opposite the direction in
which the air current (i.e., the wind) is flowing. Displacement of the at
least one moveable surface along a side of a turbine blade will increase
or decrease the overall force acting on the turbine blade depending upon
which direction (i.e., with the wind or against the wind) the at least
one moveable surface is being displaced. The change in the overall force
acting on the turbine blade will also depend upon whether the at least
one surface is being displaced along the pressure side, the suction side
or both sides, and which direction the at least one surface is being
displacement on that side (or along those sides).

[0059] As a more specific example, endless band 216F is shown in FIG. 5 as
being capable of displacement in either of a first direction DIR1 or
a second direction DIR2 at any one time. It will also be appreciated
that endless band 216F extends along both of the first and second sides
of turbine blade assembly 200 and that first side 212 will act as the
pressure side and second side 214 will operate as the suction side, as
has been described above. As endless band 216F is displaced in first
direction DIR1, the outer surface of the endless band will be
displaced into air currents flowing along second or suction side 214 and
the outer surface will be displace in a direction with the air currents
flowing along first or pressure side 212. The displacement of the outer
surface of an endless band in first direction DIR1 is expected to
generate an additional force acting on the turbine blade. Theories have
not yet been developed to explain whether this additional force is a
separate force acting on the turbine blade or whether this addition force
is better characterized as an increase in the portion of the force acting
on the turbine blade that is attributable to the differential air
pressure between the opposing first and second surfaces.

[0060] For purposes of illustration and ease of understanding, the forces
attributable to the operation of the one or more moveable surfaces are
shown in FIG. 5 as being separated into directional components with a
first directional force component being represented by arrow FBD
acting on the turbine blade in a direction approximately aligned with the
wind direction, as indicated by arrow WND, and a second directional force
component being represented by arrow FRT1 acting on the turbine
blade in a direction promoting rotation about axis AX2 (FIG. 2), as
indicated by arrow RT1. It should be clearly understood that the force
components represented by arrows FRT1 and FBD will act together
with the directional components of forces attributable to the angle of
attack and the differential air pressure.

[0061] Due to the displacement of the surface of the endless belt in first
direction DIR1, the increase in force attributable to the
displacement of the moveable surface, the portion of the force
attributable to differential air pressures and the portion of the overall
force attributable to the angle of attack are all acting in the same
direction to cause displacement of the turbine blade about the axis of
rotation. The increased force due to the sum of these directional
components will generate a corresponding increase in torque at second
body portion 118 (FIGS. 1 and 2). Such an increase in torque can be
utilized to drive an electric generator 140, such as through a suitable
transmission 142, for example, under wind speed conditions below a
theoretical minimum wind speed threshold. Or, under normal operating
conditions in which sufficient wind speed is present, such an increase in
torque could be utilized to generate a corresponding increase in
electrical output.

[0062] Additionally, it will be appreciated that the one or moveable
surfaces can be selectively operated to vary the magnitude and/or
direction of the additional force acting on the turbine blade. It will be
recognized that the distal end of a conventional turbine blade moves at a
greater instantaneous linear velocity than does the proximal end of the
turbine blade. As one example, one or more of the endless bands (e.g.,
endless bands 216A-F, 316A-F, 412 and/or 422) could be operated at
surface speeds that decrease with outward longitudinal position along the
turbine blade, such as to balance the forces acting on the turbine blade,
for example. As another example, one or more of the endless bands could
be operated at surface speeds that increase with outward longitudinal
position along the turbine blade, such as to offset any change in
effective wind direction due to the movement of the turbine blade. As a
further example, one or more of the endless bands could be selectively
operated such that some bands are displaced and other bands remain
stationary, such as to minimize maintenance and repair cost while
obtaining benefits associated with the use of the one or more moveable
surfaces.

[0063] Returning to the previous example, endless band 216F is also shown
in FIG. 5 as being capable of displacement in second direction DIR2.
As endless band 216F is displaced in second direction DIR2, the
outer surface of the endless band will be displaced with the air currents
flowing along first or pressure side 212 and the outer surface will be
displace in a direction against the air currents flowing along second or
suction side 214. The displacement of the outer surface of an endless
band in first direction DIR2 is expected to generate an additional
force acting on the turbine blade. This additional force has a second
directional force component, which is represented in FIG. 5 by arrow
FRT2, that acts on the turbine blade in a direction generally
opposite of rotation about axis AX2 (FIG. 2), which is indicated by arrow
RT1. Again, theories have not yet been developed to explain whether this
additional force is a separate force acting on the turbine blade in the
direction opposite rotation or whether this addition force is better
characterized as an decrease in the portion of the force acting on the
turbine blade that is attributable to the differential air pressure
between the opposing first and second surfaces (i.e., aerodynamic forces
other than those associated with the angle of attack). Nonetheless, the
displacement of the at least one moveable surface in the second direction
could be used to decrease the overall force being applied to the turbine
blade in the direction of rotation, such as, for example, to permit
operation of the wind turbine under wind speed conditions that would
otherwise exceed a maximum wind speed threshold for conditions of
operation of the wind turbine.

[0064] It will also be appreciated that first directional force component
FBD, which acts in the direction of the wind, can be accommodated in
any suitable manner. As one example, the structure of a turbine blade, as
well as the turbine body on which the turbine blade is supported, could
simply be manufactured to be more robust to accommodate such increased
load conditions. As another example, a blade support assembly or other
structure could be provided to buttress the one or more turbine blade
assemblies of the wind turbine. One example of a blade support assembly
could include support structure that is operatively connected to the base
structure and/or turbine body and a bearing structure that is supported
on the support structure and is adapted to operatively engage the one or
more turbine blade assemblies of the wind turbine.

[0065] In the arrangement shown in FIGS. 1 and 2, a blade support assembly
128 is shown as including a plurality of structural supports 130 that are
attached to first portion 116 of turbine body 104. Blade support assembly
128 also includes a bearing structure 132 that is supported on structural
supports 130 and is adapted to buttress turbine blade assemblies 106,
such as under increased load conditions in the direction of wind WND that
may result due to the operation of one or more moveable surfaces 126, for
example.

[0066] Blade support assembly 128 can also, optionally, include one or
more bearing elements that are supported on the one or more turbine blade
assemblies and act to abuttingly engage the bearing structure and thereby
minimize or at least reduce frictional losses between the bearing
structure and the turbine blade assemblies, as the same rotate about axis
AX2. The one or more bearing elements are schematically represented in
FIG. 2 and identified by reference numbers 134. It will be appreciated
that any suitable bearing elements could be used. As one example, a wheel
(not shown) or roller (not shown) could be supported on the turbine blade
for rotation about an axis dispose in approximate alignment with
longitudinal axis AX3.

[0067] As another example, a magnetic bearing arrangement could be used to
maintain the turbine blade assemblies in spaced relation to the bearing
structure. In one exemplary arrangement, one or more magnets (not shown),
such as permanent magnets and/or electromagnets, for example, could be
supported on each of the turbine blade assemblies. A corresponding one or
more magnets (not shown), such as permanent magnets and/or
electromagnets, for example, could be disposed along bearing structure
132. In a preferred arrangement, at least the magnets disposed along the
bearing structure are electromagnets that can be selectively operated by
a suitable control system 136. Such a control system could be disposed in
electrical communication with the electromagnets in any suitable manner,
such as by way of electrical conductor 138, for example.

[0068]FIG. 10 illustrates on example of a method 500 of operating a wind
turbine in accordance with the subject matter of the present disclosure.
Method 500 includes providing a wind turbine, such as wind turbine 100,
for example, that is operable above a theoretical minimum wind speed
condition WMIN and below a theoretical maximum wind speed condition
WMAX, as is represented by box 502 in FIG. 10. Method 500 also
includes providing at least one moveable surface (e.g., one of endless
bands 126, 216A-F, 316A-F, 412 and/or 422) and supporting the at least
one moveable surface on a turbine blade of the wind turbine, as is
represented by box 504 in FIG. 10. According to one preferred method, the
at least one moveable surface will be displaceable in first and second
lateral directions DIR1 and DIR2 with respect to at least one
side of the turbine blade. It will be appreciated that the theoretical
minimum and maximum wind speed conditions could be associated with a wind
turbine of a substantially similar construction that does not include the
at least one moveable surface. Alternately, the theoretical minimum and
maximum wind speed conditions could be associated with a wind turbine on
which the at least one moveable surface is not in operation.

[0069] Method 500 further includes displacing the at least one moveable
surface in one of the first and second lateral directions DIRSF and
at a surface speed SPDSF, as is represented by box 506 in FIG. 10.
In one example of a simplified method of operation, such as is
represented by boxes 502-506, for example, the at least one moveable
surface on a turbine blade of a wind turbine could simply be displaced in
a first pre-determined direction and at a first pre-determined surface
speed regardless of the wind conditions that the wind turbine is
experiencing. Optionally, method 500 can include additional actions that
may assist in improving the efficiency, cost effectiveness and/or output
of a wind turbine.

[0070] As such, method 500 can also, optionally, include determining the
wind conditions under which the wind turbine will be operating, as is
represented by box 508 in FIG. 10. Such an action, if performed, can
include measuring, calculating or otherwise determining a wind speed
condition WSP, such as average wind speed, for example. Other
conditions, such as maximum and/or minimum instantaneous wind speeds as
well as wind direction, for example, could also, optionally, be
determined. Method 500 can also, optionally, include determining suitable
operating parameters for the at least one moveable surface operatively
disposed along a turbine blade, as is indicated by reference number 510.
Such an action, if performed, can include any suitable measurements,
calculations and/or decisions that may be useful in determining an
operating parameter for the at least one moveable surface. For example,
such an action could include determining which direction to displace the
at least one moveable surface with respect to the pressure and/or
suctions side of the turbine blade. As another example, such an action
could include determining an approximate speed at which the at least one
moveable surface will be displaced.

[0071] One example of a plurality of actions that could be used to make a
determination of operating parameters, as is represented by reference
number 510, is shown in FIG. 10 as including an inquiry as to whether
wind speed condition WSP is less than theoretical minimum wind speed
condition WMIN, as is indicated in decision box 512. If a YES
determination is made at box 512, the current wind speed conditions are
below the theoretical minimum wind speed for operation of the wind
turbine. In such case, direction of movement DIRSF of the at least
one surface is determined to be first direction DIR1, as is
represented by box 514. In a preferred arrangement, first direction
DIR1 will correspond to movement of the surface in a direction
opposite the wind on the pressure side of a turbine blade and/or in a
direction with the wind on the suction side of a turbine blade. As
discussed above, this is expected to increase the force acting on the
turbine blade, which may permit the wind turbine to operate under wind
speed conditions below the theoretical minimum wind speed. Optionally, a
determination of a suitable surface speed SPDSF could also be made,
as is represented by box 516. Thereafter, method 500 proceeds with
displacement of the at least one moveable surface in the direction of
movement and, optionally, at the surface speed that has been previously
determined, as is indicated by box 506.

[0072] If a NO determination is made at box 512, however, the current wind
speed conditions are above the theoretical minimum wind speed. As such, a
further inquiry can be made as to whether wind speed condition WSP
is greater than the theoretical maximum wind speed condition WMAX,
as is indicated in decision box 518. IF a YES determination is made at
box 518, the current wind speed conditions are above the theoretical
maximum wind speed for operation of the wind turbine. In such case,
direction of movement DIRSF of the at least one surface is
determined to be second direction DIR2, as is represented by box
520. In a preferred arrangement, second direction DIR2 will
correspond to movement of the surface in a direction with the wind on the
pressure side of a turbine blade and/or in a direction opposite the wind
on the suction side of a turbine blade. As discussed above, this expected
to decrease the force acting on the turbine blade, which may permit the
wind turbine to operate under wind speed conditions above the theoretical
maximum wind speed. Again, a determination of a suitable surface speed
SPDSF can optionally be made, as is represented by box 522.
Thereafter, method 500 proceeds with displacement of the at least one
moveable surface in the direction of movement and, optionally, at the
surface speed that has been previously determined, as is indicated by box
506.

[0073] If a NO determination is made at box 518, the current wind speed
conditions are within the desired range for operation of the wind
turbine. In such case, direction of movement DIRSF of the at least
one surface is determined to be first direction DIR1, as is
represented by box 524. As described above, first direction DIR1
will preferably correspond to movement of the surface in a direction
opposite the wind on the pressure side of a turbine blade and/or in a
direction with the wind on the suction side of a turbine blade. This is
expected to increase the force acting on the turbine blade, which may
permit the wind turbine to generate greater output or provide other
desirable operational and/or performance characteristics. Optionally, a
determination of a suitable surface speed SPDSF could also be made,
as is represented by box 526. Thereafter, method 500 proceeds with
displacement of the at least one moveable surface in the direction of
movement and, optionally, at the surface speed that has been previously
determined, as is indicated by box 506.

[0074] While the subject matter of the present disclosure has been
described with reference to the foregoing embodiments and considerable
emphasis has been placed herein on the structures and structural
interrelationships between the component parts of the embodiments
disclosed, it will be appreciated that other embodiments can be made and
that many changes can be made in the embodiments illustrated and
described without departing from the principles hereof. Obviously,
modifications and alterations will occur to others upon reading and
understanding the preceding detailed description. Accordingly, it is to
be distinctly understood that the foregoing descriptive matter is to be
interpreted merely as illustrative of the subject matter of the present
disclosure and not as a limitation. As such, it is intended that the
subject matter of the present disclosure be construed as including all
such modifications and alterations insofar as they come within the scope
of the appended claims and any equivalents thereof.